WPT details: https://wpt.fyi/results/webauthn/conditional-mediation.https.html?label=experimental&label=master&aligned
WebAuthn Conditional Create allows websites to automatically create passkeys for existing users that have a matching password saved in their password manager.
WebAuthn Conditional Create requests let a website (aka a Relying Party or RP) create a passkey without prominent modal mediation, if the user has previously consented to credential creation. The motivating use case is commonly referred to as "passkey upgrades". I.e., if the browser/credential manager already stores an existing password credential for the same website/relying party and user, conditional create allows the the website automatically create a matching passkey. An explainer with more information is hosted in the W3C WebAuthn wiki: https://github.com/w3c/webauthn/wiki/Explainer:-Conditional-Registration-Extension